[hydrogen] optimize switch with string clauses

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 7f78d03da0db85dcb3ece1c63ba77e38791d418a..97293d5161cc07220cd0058c86303e1fa3904a7b 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -1683,6 +1683,31 @@ void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
 }
 
 
+Condition LCodeGen::EmitIsString(Register input,
+                                 Register temp1,
+                                 Label* is_not_string) {
+  __ JumpIfSmi(input, is_not_string);
+
+  Condition cond = masm_->IsObjectStringType(input, temp1, temp1);
+
+  return cond;
+}
+
+
+void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
+  Register reg = ToRegister(instr->InputAt(0));
+  Register temp = ToRegister(instr->TempAt(0));
+
+  int true_block = chunk_->LookupDestination(instr->true_block_id());
+  int false_block = chunk_->LookupDestination(instr->false_block_id());
+  Label* false_label = chunk_->GetAssemblyLabel(false_block);
+
+  Condition true_cond = EmitIsString(reg, temp, false_label);
+
+  EmitBranch(true_block, false_block, true_cond);
+}
+
+
 void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
   Operand input = ToOperand(instr->InputAt(0));
 
@@ -1710,6 +1735,41 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
 }
 
 
+static Condition ComputeCompareCondition(Token::Value op) {
+  switch (op) {
+    case Token::EQ_STRICT:
+    case Token::EQ:
+      return equal;
+    case Token::LT:
+      return less;
+    case Token::GT:
+      return greater;
+    case Token::LTE:
+      return less_equal;
+    case Token::GTE:
+      return greater_equal;
+    default:
+      UNREACHABLE();
+      return no_condition;
+  }
+}
+
+
+void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
+  Token::Value op = instr->op();
+  int true_block = chunk_->LookupDestination(instr->true_block_id());
+  int false_block = chunk_->LookupDestination(instr->false_block_id());
+
+  Handle<Code> ic = CompareIC::GetUninitialized(op);
+  CallCode(ic, RelocInfo::CODE_TARGET, instr);
+
+  Condition condition = ComputeCompareCondition(op);
+  __ test(eax, Operand(eax));
+
+  EmitBranch(true_block, false_block, condition);
+}
+
+
 static InstanceType TestType(HHasInstanceTypeAndBranch* instr) {
   InstanceType from = instr->from();
   InstanceType to = instr->to();
@@ -1987,26 +2047,6 @@ void LCodeGen::DoDeferredInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr,
 }
 
 
-static Condition ComputeCompareCondition(Token::Value op) {
-  switch (op) {
-    case Token::EQ_STRICT:
-    case Token::EQ:
-      return equal;
-    case Token::LT:
-      return less;
-    case Token::GT:
-      return greater;
-    case Token::LTE:
-      return less_equal;
-    case Token::GTE:
-      return greater_equal;
-    default:
-      UNREACHABLE();
-      return no_condition;
-  }
-}
-
-
 void LCodeGen::DoCmpT(LCmpT* instr) {
   Token::Value op = instr->op();